While watching a prior-art sound movie, a viewer often experiences a vicarious sense of involvement. Such passive involvement can be changed to active participation if the movie branches, that is, if each scene is followed by one of several alternative scenes, each having different sound or different picture or both.
An example of a prior-art branching movie is shown in U.S. Pat. No. 3,960,380 titled "Light Ray Gun and Target Changing Projectors". This system uses a pair of film projectors which present two alternatives (hit or miss) at each branch point. An example of a prior-art device for interactive voice dialog is shown in U.S. Pat. No. 4,016,540. This device does not present a motion picture. An example of a prior-art video editing system is shown in U.S. Pat. No. 3,721,757. This system displays a sequence of video excerpts specified by a control program of stored videodisc addresses which comprise a sequential (not branching) movie. To change this sequence the editor alters the program. In the present invention the viewer does not alter the program.
Push-button controlled branching movies are used for computer-assisted education systems which display a lesson segment and multiple choice questions to each student. Such a system is described by R. K. Wood in Educational and Industrial TV, May 1979, pp 31-42, in an article titled "The Utah State University Videodisc Innovations Project". Depending on the student's answer, the movie branches to a segment which contains reinforcement for correct answers, or to a segment which provides remedial lessons for wrong answers.
Applying prior-art voice-recognition techniques to control prior-art branching movies would not provide a natural dialog because of the following problem: If the number of words which a viewer of any age and sex can speak and be understood by the apparatus is sufficiently large to permit a natural conversation, then prior-art voice recognition techniques are unreliable. Conversely, if the number of words is restricted to only a few words to make voice recognition reliable, then natural conversation would not result. It is also necessary for the picture to be responsive to a viewer's voice and be synchronized with the spoken reply. These problems are not addressed in the prior art.